Correct formula of calomel is

Options

A. `Hg_(2)Cl_(2)`
B. `HgCl_(2)`
C. `HgCl_(2).H_(2)O`
D. `HgSO_(4)`

Answer

To determine the correct formula of Calomel, we need to analyze the options provided and understand the composition of Calomel.

### Step-by-Step Solution:

1. **Identify the Substance**: Calomel is a compound that contains mercury and chlorine. It is important to know the components of Calomel to find its correct formula.

2. **Understand the Oxidation States**: In Calomel, mercury (Hg) is in the +1 oxidation state. This is crucial because it helps us determine how many mercury atoms are present in the formula.

3. **Examine the Options**: We have the following options:
- Option 1: Hg2Cl2
- Option 2: HgCl2
- Option 3: HgCl2 x H2O
- Option 4: HgSO4

4. **Analyze Each Option**:
- **Hg2Cl2**: This formula suggests that there are two mercury atoms and two chloride ions. Given that mercury is in the +1 oxidation state, this is consistent with Calomel.
- **HgCl2**: This formula indicates that mercury is in the +2 oxidation state, which does not correspond to Calomel.
- **HgCl2 x H2O**: This is a hydrated form of mercury(II) chloride, which is not Calomel.
- **HgSO4**: This is mercury(II) sulfate, which is also not Calomel.

5. **Conclusion**: The only option that correctly represents Calomel, which is mercury(I) chloride, is Hg2Cl2.

### Final Answer:
The correct formula of Calomel is **Hg2Cl2**.

---